Google has now announced they are looking into retaining customer search data for longer than 18 months IF the person specifically opts into this system. Assuming this option is not automatically ticked when customers go to the relevant page, this does reassure me. Although the potential to abuse such data will still exist, I can see how some users would not be happy with potentially losing 6 months of their own search data, as was possible when Google announced they would cut the retention time from 24 to 18 months, after criticism from several groups.